"Sick bottom
paint" is film fatigue of the various layers of
paint, failing at different rates. I''ve done boats with sanders (mucho disk eating, pushing bottom
paint into every crevice and pinhole) and chemical strippers. I''m hoping the next time I''ll have enough scratch to pay someone else to do it. I''ve now found I can strip a 40'' fin keel sailboat in 8 hours to gelcoat. Another day with orbital sander and schmundo (West filler), should be able to barrier coat 3rd day and, if you do it right, put the bottom
paint on and launch day 4. Depends on the manufacturer''s recommendations, which you should read carefully first. Orbital sanders, toxic strippers (methylene chloride - ewww), etc. costs you in materials and labor. Walnut shells WILL cut gelcoat, but the trick is adjusting the PSI of the blast correctly. Silica sand blasting is absolutely wrong. I use bicarbonate of soda. The process requires the machine, the media, and a minimum 185CFM compressor (tow behind the truck kind). By machine, I mean the right machine, not a reconfigured sandblaster. I''ve also developed a method for recovering a large percentage of waste
paint. All EPA acknowledged. Someday I''ll actually have time to do something with it, but then I''d have to come back to America. Too damn sunny down here every day. KW, VIRGIN SURFACING, LLC.